Title: Good and Bad Bacteria Strains Found in P. acnes

Research conducted at UCLA with scientists from Washington University in St. Louis and the Los Angeles Biomedical Research Institute has made an interesting discovery about Propionibacterium acnes that may affect the prevention and treatment of the disorder. In a Journal of Investigative Dermatology article, the researchers identified that some strains in the bacteria caused acne, whereas other strains resulted in healthy skin.

To compare the skin microbiome at the strain level and genome level, the researchers sampled the pilosebaceous units of 49 acne patients and 52 healthy individuals by removing P. acnes bacteria with OTC pore strips. After extracting the microbial DNA from the strips, the researchers tracked a genetic marker to identify the bacterial strains in each volunteer's pores and recorded whether the person suffered from acne. They then cultured the bacteria from the strips to isolate more than 1,000 strains.

Metagenomic analysis demonstrated that although the relative abundances of P. acnes were similar, the strain population structures were significantly different in the two groups. Certain strains were highly associated with acne, and other strains were enriched in healthy skin. Washington University scientists sequenced 66 previously unreported P. acnes strains and compared 71 P. acnes genomes, enabling researchers to identify genes unique to each strain that are associated with acne or healthy skin.

The researchers found two strains of P. acnes that appeared in 20% of those with acne but in few healthy skin individuals. In addition, they found a third strain that is common in healthy skin but not found in acneic skin. The researchers believe the third strain may defend the skin from harmful acne bacteria and may be used as a future skin care target to prevent or treat acne.

Future plans for the researchers include identifying materials that can kill the bad strains of P. acnes while preserving the good strains, and they may investigate a probiotic cream to do this. They also plan to look into viruses to kill acne-related bacteria and to develop a skin test to predict whether an individual will suffer from harsh acne.

The researchers emphasize that this study demonstrates a previously unreported paradigm of commensal strain populations that could explain the pathogenesis of human diseases.

The research was supported by a grant (UH2AR057503) from the National Institutes of Health's Human Microbiome Project through the National Institute of Arthritis and Musculoskeletal and Skin Diseases. Co-authors from UCLA include: co-first author Sorel Fitz-Gibbon; Bor-Han Chiu; Lin Nguyen; Christine Du; Minghsun Liu, MD; David Elashoff; Jenny Kim, MD, PhD; Anya Loncaric; Robert Modlin, MD; and Jeff F. Miller of UCLA. Other researcher included Erica Sodergren of Washington University; and Marie Erfe, MD, of LA BioMed.